At 04:15 PM 1/21/2007, W2RU - Bud Hippisley wrote:
>Cecil Moore wrote:
>
> >> From: W2RU - Bud Hippisley <W2RU@frontiernet.net>
> >> Subject: Re: [TowerTalk] dipole length adjustment
> >> What's simple about getting up from the rig, walking to the coat closet,
> >> getting my coat and hat and boots and mittens, going outside to my tuner
> >> that's located at the feedpoint of my antenna, turning the knobs in -20
> >> degree weather, and returning to the house where I go through the
> >> reverse process, only to find the DX that I was going to chase has
> >> disappeared?
> >
> >
> > Point is, you don't have to do that with an SG-230.
>
>
>Point is, I can't find an SG-230 that runs 1500 watts.
Bud makes an interesting point here. Certainly, for 100-200W, it's
pretty easy to find a reasonably low loss auto or remote tuner so the
"coax/tuner at feedpoint/easy routing of coax" alternative is
competitive with the "tuner at transmitter/openwire line/a bit more
pain to route" approach.
But at 1500W, there aren't so many alternatives. 1500W automatic or
remote tuners are going to be bigger and bulkier (and, so, a bit
trickier to install at the feedpoint), so the system tradeoff might
be more competitive for the openwire line approach.
For instance, you could take the existing tuner Bud is using, put it
in a weather proof enclosure, add some servos or steppers, etc. But
that's probably more of a pain than just running the openwire line.
It might well be, though, that as time goes on and technology
improves, it will get easier to put the adjustable matching network
at the feedpoint, assuming there's a reasonable demand.
Speaking to the latter, I doubt there's a whole lot of people running
a kilowatt to an untuned low loss, low gain antenna (at least ones
who'd be willing to pay the few thousand dollars a well integrated
system with coax feed). The system designs if you positively have to
have coax feed probably tend to look like full custom (i.e. not an
off the shelf product) or some sort of lossy broadband radiator (like
the B&W loaded folded dipole)
Jim, W6RMK
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|